The present invention relates to the use of nonwoven, three dimensional fibrous web articles that employ phenolic particles to remove gasket material from a surface.
Gaskets are employed in a variety of mechanical applications (e.g., assembling the components of internal combustion engines) to effect a seal between two mating surfaces joined together by fasteners. Gasketing materials are generally softer and more compliant than the surfaces of the materials that they are sealing together. This compliance can aid in accommodating irregularities in the surfaces being mated, facilitating, for example, uniform fastener tension. In some applications, gaskets may be adhered with an adhesive to one or all mating surfaces. Even in the absence of an adhesive, however, sustained heat and pressure may cause the gasket material to autogenously adhere to one or more of the mating surfaces.
During the course of requisite maintenance and repair operations, it is frequently required to separate surfaces mated with a gasket(s). During the process of separating the surfaces, the gasket is almost always damaged so that re-use is prohibited. Further, residual gasket material frequently remains on one or more of the formerly mated surfaces. To reuse parts having residual gasket material thereon, it is necessary to remove the residual gasket material without damaging the mating surface. The presence of residual gasket material, and/or damage to a mating surface may adversely effect the quality of the seal between mated surfaces.
A number of methods for removing residual gasket material from mating surfaces are known in the art. For example, scrapers have been used to remove such residuals, but even when automated, their use is arduous and may cause inadvertent damage to the mating surfaces, especially if the scraper blades are made of metal. Solvents or other chemical compounds have been also been employed to remove residual gasket material. While chemicals have been effective for such purpose, there can be problems relative to disposal of contaminated detritus and introduction of volatiles into the environment.
Manual or automated employment of abrasive articles, especially those comprising lofty, nonwoven substrates adhered by resinous binder and coated with abrasive particles, have offered improved productivity for removing gasket material. Such articles typically do not damage the surface of the mating surface being cleaned, although when aggressively used with powered tools and/or under high contact pressures mating surface(s) can be damaged. Further, portions of the relatively hard abrasive particles typically dislodge from the abrasive article during use, and may lead to undesirable contamination of the mating and/or other neighboring surfaces.
There is a need for quick removal of residual gasket materials, without damaging the underlying surface (i.e., significantly adversely altering the mating surfaces), without the liberation of hard particles, and with no disposal or environmental complications.
The present invention provides methods for removing gasket material from a substrate (e.g., aluminum, cast iron, and alloys thereof), using an abrasive article (e.g., sheets, discs, and endless belts) comprising:
a scrim having a first major surface;
a nonwoven, three dimensional fibrous web having first and second major surfaces,
wherein the first major surface of the fibrous web is needle tacked to the first major surface of the scrim; and
an abrasive layer having work surface secured to the second major surface of the fibrous web, the abrasive layer comprised of binder and a plurality of phenolic particles, wherein the phenolic particles at the work surface are free of abrasive particles (i.e., particles having a mohs hardness of greater than 7) larger than 6 micrometers. Preferably, at least a portion (more preferably, at least a majority, even more preferably at least 60, 70, 75, 80, 90, 95, or even 100 percent by weight) of the phenolic particles are in the range from 150 micrometers to 2400 micrometers (more preferably, 400 micrometers to 850 micrometers, or even 150 micrometers to 1000 micrometers) in size. Optionally, at least a portion of the phenolic particles comprise filler. Preferably, all the phenolic particles are free of abrasive particles larger than 6 micrometers. Typically, the first major surface of the scrim is substantially co-extensive with the first major of the fibrous web.
In one embodiment, the present invention provides a method of removing gasket material from a substrate, the method comprising:
providing an abrasive article described herein having a work surface;
frictionally engaging at least a portion of the work surface of the abrasive article with the gasket material to be removed; and
inducing relative motion between the abrasive article and the gasket material to be removed to remove at least a portion of the gasket material.
In another embodiment, the present invention provides a method of removing gasket material from a substrate, the method comprising:
providing power driven (e.g., electric motor driven or air driven) abrasive device comprising a rotatable shaft having an abrasive disc described herein having a work surface attached thereto; and
energizing the power driven abrasive device such that the rotatable shaft rotates; and
frictionally engaging at least a portion of the work surface of the rotating abrasive disc with the gasket material to be removed such that at least a portion of the gasket material is removed.
Preferably, the gasket material is removed from a substrate surface without changing the surface roughness of the substrate xcex94Ra by not more than 9 microinches (0.23 micrometer), more preferably, not more than 6 microinches (0.15 micrometer).